scholarly journals Ectopic methylation of a single persistently-unmethylated CpG in the promoter of the vitellogenin gene abolishes its inducibility by estrogen through attenuation of USF binding

2019 ◽  
Author(s):  
Lia Kallenberger ◽  
Rachel Erb ◽  
Lucie Kralickova ◽  
Andrea Patrignani ◽  
Esther Stöckli ◽  
...  
Keyword(s):  
Transcriptional Control ◽  
Dna Demethylation ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Reporter System ◽  
Active Dna Demethylation ◽  
E Box ◽  
Vitellogenin Gene

ABSTRACTThe enhancer/promoter of the vitellogenin II (VTG) gene has been extensively studied as a model system of vertebrate transcriptional control. While deletion mutagenesis and in vivo footprinting identified the transcription factor (TF) binding sites governing its tissue specificity, DNase hypersensitivity- and DNA methylation studies revealed the epigenetic changes accompanying its hormone-dependent activation. Moreover, upon induction with estrogen (E2), the region flanking the estrogen-responsive element (ERE) was reported to undergo active DNA demethylation. We now show that although the VTG ERE is methylated in embryonic chicken liver and in LMH/2A hepatocytes, its induction by E2 was not accompanied by extensive demethylation. In contrast, E2 failed to activate a VTG enhancer/promoter-controlled luciferase reporter gene methylated by SssI. Surprisingly, this inducibility difference could be traced not to the ERE, but rather to a single CpG in an E-box (CACGTG) sequence upstream of the VTG TATA box, which is unmethylated in vivo, but methylated by SssI. We demonstrate that this E-box binds the upstream stimulating factor USF1/2. Selective methylation of the CpG within this binding site with an E-box-specific DNA methyltranferase Eco72IM was sufficient to attenuate USF1/2 binding in vitro and abolish the hormone-induced transcription of the VTG gene in the reporter system.

scholarly journals Ectopic Methylation of a Single Persistently Unmethylated CpG in the Promoter of the Vitellogenin Gene Abolishes Its Inducibility by Estrogen through Attenuation of Upstream Stimulating Factor Binding

2019 ◽  
Vol 39 (23) ◽  
Author(s):  
Lia Kallenberger ◽  
Rachel Erb ◽  
Lucie Kralickova ◽  
Andrea Patrignani ◽  
Esther Stöckli ◽  
...  
Keyword(s):  
Dna Methyltransferase ◽  
Transcriptional Control ◽  
Dna Demethylation ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Reporter System ◽  
E Box ◽  
Stimulating Factor

ABSTRACT The enhancer/promoter of the vitellogenin II gene (VTG) has been extensively studied as a model system of vertebrate transcriptional control. While deletion mutagenesis and in vivo footprinting identified the transcription factor (TF) binding sites governing its tissue specificity, DNase hypersensitivity and DNA methylation studies revealed the epigenetic changes accompanying its hormone-dependent activation. Moreover, upon induction with estrogen (E2), the region flanking the estrogen-responsive element (ERE) was reported to undergo active DNA demethylation. We now show that although the VTG ERE is methylated in embryonic chicken liver and in LMH/2A hepatocytes, its induction by E2 was not accompanied by extensive demethylation. In contrast, E2 failed to activate a VTG enhancer/promoter-controlled luciferase reporter gene methylated by SssI. Surprisingly, this inducibility difference could be traced not to the ERE but rather to a single CpG in an E-box (CACGTG) sequence upstream of the VTG TATA box, which is unmethylated in vivo but methylated by SssI. We demonstrate that this E-box binds the upstream stimulating factor USF1/2. Selective methylation of the CpG within this binding site with an E-box-specific DNA methyltransferase, Eco72IM, was sufficient to attenuate USF1/2 binding in vitro and abolish the hormone-induced transcription of the VTG gene in the reporter system.

scholarly journals Cyclin A expression is under negative transcriptional control during the cell cycle.

1996 ◽  
Vol 16 (7) ◽  
pp. 3789-3798 ◽  
Author(s):  
X Huet ◽  
J Rech ◽  
A Plet ◽  
A Vié ◽  
J M Blanchard
Keyword(s):  
Cell Cycle ◽  
Transcriptional Repression ◽  
Transcriptional Control ◽  
Cell Cycle Progression ◽  
Cyclin A ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Proliferating Cells

Transcription of the gene coding for cyclin A, a protein required for S-phase transit, is cell cycle regulated and is restricted to proliferating cells. To further explore transcriptional regulation linked to cell division cycle control, a genomic clone containing 5' flanking sequences of the murine cyclin A gene was isolated. When it was fused to a luciferase reporter gene, it was shown to function as a proliferation-regulated promoter in NIH 3T3 cells. Transcription of the mouse cyclin A gene is negatively regulated by arrest of cell proliferation. A mutation of a GC-rich sequence conserved between mice and humans is sufficient to relieve transcriptional repression, resulting in a promoter with constitutively high activity. In agreement with this result, in vivo footprinting reveals a protection of the cell cycle-responsive element in G0/early G1 cells which is not observed at later stages of the cell cycle. Moreover, the footprint is present in dimethyl sulfoxide-induced differentiating and not in proliferating Friend erythroleukemia cells. Conversely, two other sites, which in vitro bind ATF-1 and NF-Y, respectively, are constitutively occupied throughout cell cycle progression.

A Novel Approach for Monitoring TGF-ß Signaling in vivo in Colon Cancer

2020 ◽  
Author(s):  
Bin-hao Zhang ◽  
Chao Wang ◽  
Wei Dong ◽  
Xin Chen ◽  
Chao Leng ◽  
...  
Keyword(s):  
Colon Cancer ◽  
Liver Metastasis ◽  
Luciferase Activity ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Reporter System ◽  
Antitumor Effects ◽  
Long Term Treatment

Abstract The TGF-β receptor kinase inhibitors (TRKI) have been reported to inhibit tumorigenicity in colon cancer. However, there is no direct evidence showing that these inhibitors function through inhibiting the TGF-β- mediated tumor-promoting effects in vivo. We established a TGF-β inducible reporter system by inserting a luciferase reporter gene to the vector downstream of TGF-β-inducible promoter elements, and transfected it into colon cancer cell lines. TRKIs SB431542 and LY2109761 were used to treat TGF-β inducible cells in vitro and in vivo. The luciferase activity was induced 5.24 folds by TGF-β in CT26 inducible cells, while it was marginally changed in MC38 inducible cells lacking Smad4 expression. Temporary treatment of mice with SB431542 inhibited the TGF-β pathway and TGF-β induced bioluminescence activity in vivo. Long-term treatment with LY2109761 inhibited tumorigenicity and liver metastasis in vivo in concomitant with reduced luciferase activity in the tumor. In this study, we established a model to monitor the TGF-β pathway in vivo and to compare the antitumor effects of TRKIs. Based on this novel experimental tool, we provided direct evidences that LY2109761 inhibits tumorigenicity and liver metastasis by blocking the pro-oncogenic functions of TGF-β in vivo.

scholarly journals Impact of RARα and miR-138 on retinoblastoma etoposide resistance

Tumor Biology ◽  
2021 ◽  
Vol 43 (1) ◽  
pp. 11-26
Author(s):  
Maike Busch ◽  
Natalia Miroschnikov ◽  
Jaroslaw Thomas Dankert ◽  
Marc Wiesehöfer ◽  
Klaus Metz ◽  
...  
Keyword(s):  
Cell Viability ◽  
Cell Lines ◽  
Cancer Progression ◽  
Treated Patient ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Gene Assay ◽  
The Impact

BACKGROUND: Retinoblastoma (RB) is the most common childhood eye cancer. Chemotherapeutic drugs such as etoposide used in RB treatment often cause massive side effects and acquired drug resistances. Dysregulated genes and miRNAs have a large impact on cancer progression and development of chemotherapy resistances. OBJECTIVE: This study was designed to investigate the involvement of retinoic acid receptor alpha (RARα) in RB progression and chemoresistance as well as the impact of miR-138, a potential RARα regulating miRNA. METHODS: RARα and miR-138 expression in etoposide resistant RB cell lines and chemotherapy treated patient tumors compared to non-treated tumors was revealed by Real-Time PCR. Overexpression approaches were performed to analyze the effects of RARα on RB cell viability, apoptosis, proliferation and tumorigenesis. Besides, we addressed the effect of miR-138 overexpression on RB cell chemotherapy resistance. RESULTS: A binding between miR-138 and RARα was shown by dual luciferase reporter gene assay. The study presented revealed that RARα is downregulated in etoposide resistant RB cells, while miR-138 is endogenously upregulated. Opposing RARα and miR-138 expression levels were detectable in chemotherapy pre-treated compared to non-treated RB tumor specimen. Overexpression of RARα increases apoptosis levels and reduces tumor cell growth of aggressive etoposide resistant RB cells in vitro and in vivo. Overexpression of miR-138 in chemo-sensitive RB cell lines partly enhances cell viability after etoposide treatment. CONCLUSIONS: Our findings show that RARα acts as a tumor suppressor in retinoblastoma and is downregulated upon etoposide resistance in RB cells. Thus, RARα may contribute to the development and progression of RB chemo-resistance.

scholarly journals LINC00839 Knockdown Restrains The Metastatic Behaviors of Nasopharyngeal Carcinoma By Sponging miR-454-3p

2021 ◽  
Author(s):  
Feng Ying Zhang ◽  
Xia Li ◽  
Ting Ting Huang ◽  
Mei Ling Xiang ◽  
Lin Lin Sun ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Underlying Mechanism ◽  
Luciferase Reporter ◽  
Regulatory Function ◽  
Migration And Invasion ◽  
Luciferase Reporter Gene ◽  
Non Coding Rna ◽  
Invasive Capacity

Abstract Background Long intergenic non-coding RNA 00839 (LINC00839) has been verified as a cancer-promoting gene in malignancies. However, the significance of LINC00839 in nasopharyngeal carcinoma (NPC) has yet to be elaborated, as well as its underlying mechanism.Methods LINC00839 and miR-454-3p relative expression levels in NPC cells were examined by qRT-PCR. The growth of cells was examined by CCK-8 and colony formation assays. Cell migration and invasion were examined by wound healing and Transwell experiment, respectively. The binding sequence of LINC00839 and miR-454-3p was confirmed by the luciferase reporter gene experiment. The regulatory function of LINC00839 and miR-454-3p on c-Met was investigated by western blot.Results Here, we revealed that LINC00839 was elevated in NPC. Both LINC00839 knockdown and upregulation of miR-454-3p suppressed NPC cells proliferation, invasive capacity and EMT in vitro. Besides, LINC00839 was validated as a miR-454-3p “sponge”, and upregulation of LINC00839 could reverse miR-454-3p-mediated functions in NPC C666-1 and SUNE-1 cells. Furthermore, c-Met was determined to be targeted by miR-454-3p. Notably, c-Met was downregulated by LINC00839 knockdown through sponging miR-454-3p. In vivo, LINC00839 knockdown resulted in a slower tumor growth.Conclusions Altogether, knockdown of LINC00839 inhibits the aggressive properties of NPC cells via sponging miR-454-3p and regulating c-Met.

scholarly journals Circular RNA CDR1as Inhibits the Metastasis of Gastric Cancer through Targeting miR-876-5p/GNG7 Axis

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jiajia Jiang ◽  
Rong Li ◽  
Junyi Wang ◽  
Jie Hou ◽  
Hui Qian ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Epithelial Mesenchymal Transition ◽  
Circular Rna ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Luciferase Reporter Gene ◽  
Mesenchymal Transition ◽  
Underlying Mechanisms

Circular RNA CDR1as has been demonstrated to participate in various cancer progressions as miRNA sponges. The exact underlying mechanisms of CDR1as on gastric cancer (GC) metastasis remain unknown. Here, we found that CDR1as knockdown facilitated GC cell migration and invasion while its overexpression inhibited the migration and invasion abilities of GC cells in vitro and in vivo. Moreover, epithelial-mesenchymal transition- (EMT-) associated proteins and MMP2 and MMP9 were downregulated by CDR1as. Bioinformatics analysis combined with dual-luciferase reporter gene assays, western blot, RT-qPCR analysis, and functional rescue experiments demonstrated that CDR1as served as a miR-876-5p sponge and upregulated the target gene GNG7 expression to suppress GC metastasis. In summary, our findings indicate that CDR1as suppresses GC metastasis through the CDR1as/miR-876-5p/GNG7 axis.

CircRNA_0092516 regulates chondrocyte proliferation and apoptosis in osteoarthritis through the miR-337-3p/PTEN axis

2020 ◽  
Author(s):  
Zhihui Huang ◽  
Wenming Ma ◽  
Jinhuai Xiao ◽  
Xiaoyu Dai ◽  
Weiqi Ling
Keyword(s):  
Cell Apoptosis ◽  
Luciferase Reporter ◽  
Circular Rnas ◽  
Mechanism Analysis ◽  
Potential Mechanism ◽  
Luciferase Reporter Gene ◽  
Chondrocyte Proliferation ◽  
In Vivo Experiments

Abstract The dysregulation of circular RNAs (circRNAs) has been identified in various human diseases. Here, we probed into the potential mechanism of circRNA_0092516 in osteoarthritis (OA). The expression of circRNA_0092516 was tested by quantitative real-time PCR. MTT, flow cytometry and western blot were applied to confirm the functions of circRNA_0092516 in vitro. Besides, RNA pull-down and dual-luciferase reporter gene experiments were applied to probe into the mechanism. circRNA_0092516 was raised in the tissues of OA patients and chondrocytes stimulated by IL-1β. The potential mechanism analysis expounded that circRNA_0092516 bound to miR-337-3p, and the interference with circRNA_0092516 boosted chondrocyte proliferation and restrained cell apoptosis through the miR-337-3p/phosphatase and tensin homolog (PTEN) axis, thereby improving OA. In-vivo experiments expounded that circRNA_0092516 regulated cartilage production through miR-337-3p. Overall, our data expounded that the interference with circRNA_0092516 boosted chondrocyte proliferation and restrained cell apoptosis through the miR-337-3p/PTEN axis, eventually slowed down the progress of OA.

scholarly journals Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity

Viruses ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 403 ◽  
Author(s):  
Courtney N. Dial ◽  
Patrick M. Tate ◽  
Thomas M. Kicmal ◽  
Bryan C. Mounce
Keyword(s):  
Protease Activity ◽  
Rna Virus ◽  
Coxsackievirus B3 ◽  
Eukaryotic Cells ◽  
Luciferase Reporter ◽  
Reporter System ◽  
3C Protease ◽  
Picornavirus Infection

Polyamines are small positively-charged molecules abundant in eukaryotic cells that are crucial to RNA virus replication. In eukaryotic cells, polyamines facilitate processes such as transcription, translation, and DNA replication, and viruses similarly rely on polyamines to facilitate transcription and translation. Whether polyamines function at additional stages in viral replication remains poorly understood. Picornaviruses, including Coxsackievirus B3 (CVB3), are sensitive to polyamine depletion both in vitro and in vivo; however, precisely how polyamine function in picornavirus infection has not been described. Here, we describe CVB3 mutants that arise with passage in polyamine-depleted conditions. We observe mutations in the 2A and 3C proteases, and we find that these mutant proteases confer resistance to polyamine depletion. Using a split luciferase reporter system to measure protease activity, we determined that polyamines facilitate viral protease activity. We further observe that the 2A and 3C protease mutations enhance reporter protease activity in polyamine-depleted conditions. Finally, we find that these mutations promote cleavage of cellular eIF4G during infection of polyamine-depleted cells. In sum, our results suggest that polyamines are crucial to protease function during picornavirus infection. Further, these data highlight viral proteases as potential antiviral targets and highlight how CVB3 may overcome polyamine-depleting antiviral therapies.

scholarly journals MiR-203 Determines Poor Outcome and Suppresses Tumor Growth by Targeting TBK1 in Osteosarcoma

2015 ◽  
Vol 37 (5) ◽  
pp. 1956-1966 ◽  
Author(s):  
Shiping Liu ◽  
Peng Feng
Keyword(s):  
Cell Growth ◽  
Cell Lines ◽  
Cancer Progression ◽  
Human Cancer ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Poor Overall Survival ◽  
Gene Assay

Background/Aims: Increasing evidence has shown that miR-203 plays important role in human cancer progression. However, little is known about the function of miR-203 in osteosarcoma (OS). Methods: The expression of miR-203 in OS tissues and cell lines were examined by qRT-PCR. The biological role of miR-20 in OS cell proliferation was examined in vitro and in vivo. The targets of miR-203 were identified by a luciferase reporter gene assay. Results: miR-203 was down regulated in OS tissues and cell lines; decreased miR-203 was associated with a poor overall survival in OS patients. Restoration of miR-203 expression reduced cell growth in vitro and suppressed tumorigenicity in vivo. In contrast, inhibition of miR-203 stimulated OS cell growth both in vitro and in vivo. In addition, TANK binding kinase 1 (TBK1) was identified as a direct target of miR-203; overexpression of TBK1 partly reversed the suppressive effects of miR-203. Furthermore, TBK1 was found up-regulated and inversely correlated with miR-203 in OS tissues. Conclusion: Taken together, these findings suggest that miR-203 acts as a tumor suppressor via regulation of TBK1 expression in OS progression, and miR-203 may be a promising therapeutic target for OS.

scholarly journals PRPF6 Induces the Alternative Splicing of lncRNA SNHG16 To Promote Progression and Paclitaxel Resistance of Ovarian Cancer via Regulating GATA3 Transcription

2021 ◽  
Author(s):  
Han Wang ◽  
Yingying Zhou ◽  
Siyang Zhang ◽  
Ya Qi ◽  
Min Wang
Keyword(s):  
Ovarian Cancer ◽  
Alternative Splicing ◽  
Epithelial To Mesenchymal Transition ◽  
Binding Protein ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Mesenchymal Transition ◽  
Gene Assay

Abstract Background Small nucleolar RNA host gene 16 (SNHG16) and pre-mRNA processing factor 6(PRPF6) play vital roles in regulatory mechanisms of multiple cancers, but the mechanisms in ovarian cancer (OC) remains poorly understood. Methods The expression of SNHG16 transcripts-SNHG16-L/S in OC tissues were analyzed by real-time PCR (RT-PCR). The expression of PRPF6 in OC tissues were detected by Immunohistochemistry (IHC). Tumorigenesis, epithelial-to-mesenchymal transition (EMT) and PTX-resistance were detected by western blot, transwell, CCK-8 assays, colony formation assays and flow cytometry analyses. Molecular interactions were examined by dual-luciferase reporter gene assay, RNA immunoprecipitation (RIP) and chromatin immunoprecipitation (ChIP). Results The results indicated the expression of SNHG16-L/S was opposite in chemo-resistance and chemo-sensitivity tissues of OC. And SNHG16-L/S had different effects on the progression and PTX-resistance of OC cells. SNHG16-L inhibited GATA binding protein 3 (GATA3) transcription through CCAAT/enhancer-binding protein b (CEBPB) to further promote tumorigenesis, EMT and PTX-resistance of OC. Moreover, PRPF6 was upregulated in chemo-resistance tissues of OC. PRPF6 promoted tumorigenesis and PTX-resistance in vitro and in vivo. Mechanistically, PRPF6 induced the alternative splicing of SNHG16 to downregulate SNHG16-L, which further mediated progression and PTX-resistance through upregulating GATA3 in OC. Conclusions Totally, the results demonstrated that PRPF6 promoted progression and PTX-resistance in OC through SNHG16-L/CEBPB/GATA3 axis. Thus, PRPF6 may become a valuable target for OC therapy.

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